248 ADDITIONS-RECENT SPECIES. 



well with Philippi's description of D. texasianum. We are, there- 

 fore, disposed to rank D. gouldii as a form of texasianum, which has 

 many years of priority of description. To the references should be 

 added D. texasianum Ph., ROEMER, Texas, p. 454 (1849). 



Possibly the " D. pseudosexagonum Dh." reported from Tucacas, 

 Venezuela, by Higgins & Marratt, Moll. Voy. ' Argo,' Proc. Lit. 

 and Philos. Soc. Liverpool, xxxi, 1877, p. 416, is this species. There 

 are many errors in the ' Argo ' identifications. 



D. BEDNALLI Pilsbry & Sharp, n. sp. PI. 39, figs. 1, 2, 3. 



Shell soiled or Isabella-whitish, moderately arcuate, the curvature 

 mainly posterior. Sculpture : at and near the apex with 7 strong, 

 rounded ribs separated by deeply concave and decidedly wider in- 

 tervals ; passing anteriorly the ribs become lower and wider, and 

 tend to split by the appearance of progressively deepening sulci on 

 their side slopes, so that at the aperture there are about 10 very low 

 ribs of unequal prominence, besides some incipient ones; the inter- 

 vals shallow and narrower than the ribs. Growth stria3 fine and 

 rather inconspicuous throughout, no longitudinal striation. Aper- 

 ture subcircular, retaining a slightly hexagonal form, as long as 

 wide ; apex rather large, the orifice small, oval, longer than wide, 

 with thick walls ; no slit or notch. Length 19, diam. at aperture 

 2 - 8, at apex 1*3 mill. 



St. Vincent's Gulf, South Australia (W. T. Bednall). 



f D. octogonum of Adcock's Hand List of the Aquatic Mollusca 

 inhabiting S. Australia, p. 10 (1893). 



The fundamental form may prove to be six-ribbed rather than 

 seven-ribbed. The two costate species of this region, D. tasmanien- 

 se and D. weldianum, are not known to me by specimens, and 

 neither of them have been figured, but from the brief descriptions 

 published (see p. 9) this species seems distinct from either of them. 



D. CONSPICUUM Melvill. PI. 33, fig. 60. 



Shell shining, subulate, arcuate, milk-white, longitudinally deli- 

 cately striated, the striae unequal, here thin and there thicker, 

 spirally irregularly concentrically encircled by lira; at the apex 

 octagonal, toward base vanishing, the base itself very smooth, rotund. 

 Length If, diam. f\ inch (Melv.~). 



Karachi. 



